1. Field of the Invention
The invention concerns a mechanism for the braking of the unwinding of a bundle of metallic wire housed in a container drum and aimed particularly at feeding soldering machines, in particular those operating continuously, with automatic advancing of the wire that constitutes the weld metal.
2. Description of the Prior Art
Coils of metal wire are used, particularly in the field of continuous soldering machines, where said wire is unrolled and carried to the soldering point where it is melted to join the two parts to be soldered.
When the quantity of wire being used is large, instead of being wound in rolls of a few kilogrammes in weight, the metallic wire, is contained as a bundle of various quintals inside a drum with a positioning cylindrical core, so that it is capable of feeding the soldering machine for a long period of time, eliminating in this way its frequent stoppage due to lack of the same soldering wire.
This type of feeder drum is positioned, when operative, with its axis in vertical position and the wire of the bundle is pulled up by a dragging unit. Due to the extreme elasticity of the wire and of its tendency to straighten out, when it is pulled towards the outside, various turns tend to rise together and they can become tangled among each other so as to provoke the stoppage of its advancement. This inconvenience is being presently avoided by the use of a crown shaped weight, placed inside the drum and on the bundle of wire with the aim of avoiding the rising of various turns at the same time and therefore their tangling up.
However, there is a clearance between said crown and the inner surface of the drum's contour and between the crown and the surface of the inner tubular trunk which keeps the bundle in position, without said clearance, due to the fact that the drums are not strictly identical to one another, the crown shaped weight could adhere to said surfaces and not slide enough to maintain itself adherent to the bundle, as the wire is used, or could impede the unwinding of the wire because of the pressure placed on the contours of the drum where it adheres, and would end up by carrying out a blockage on the wire that should instead move forward.
If instead the crown shaped weight should have a relatively ample clearance compared to the internal surface of the drum and of the internal tubular trunk, the movement of the coils at the top of the bundle, determined by the unrolling movement, could bring said turns or parts of them above the pressure disk and interact with it to form a knot, therefore blocking the unwinding of the bundle and consequently of the soldering machine.